The restricted possibilities of surgical methods and of the chemotherapy make urgent the further development of new methods of treatment of the oncological patients. Nowadays particular attention is given to the anti-angiogenic therapy which mode of action is based on the repression of the growth of tumor vessels.
The tumor development has two main stages: the prevascular and vascular ones. During the first stage the tumor grows receiving nutritive substances and oxygen by means of the their diffusion from the patient's vessels which does not allow the tumor to grow over the volume of few cubic millimeters. The following tumor growth requires it's transition to the second stage which is characterized by the tumor vascularisation (Folkman J., “What is evidence that tumors are angiogenesis dependent?” J. Natl. Cancer Inst., 1990, v.82, 4-6). The appearance of blood vessels strongly enhances the nutrition of the tumor which leads to it's intensified growth and augments the probability of metastases (Hanahan D., Folkman J. “Patterns and emerging mechanisms of the angiogenic switch during tumorigenesis”. Cell, 1996, v. 86, 353-364). The use of anti-angiogenic substances results in the prevention of tumor vessels growth and accordingly in the suppression of the second phase of growth.
One of the well known ways of the tumor growth prevention is the vaccination of the patient aiming to overcome the immune tolerance in respect to endothelial cells (EC) lining the vessels' intima. The cell- and humoral cytotoxicity results in the death of EC which hinders the formation of tumor vessels and as consequence causes the destruction of the malignant cells. Various methods of the preparation of antigens for such vaccines are known; most close to our invention are vaccines based on the proper EC antigens.
Literature sources suggest the method of obtaining the vaccine based on the use of xenogeneic EC i.e. using endothelial cells from another biological species (e.g. Wei Y., “Immunotherapy of tumors with xenogeneic endothelial cells as a vaccine”, Nature Medicine, 2000, v. 6, 1160-1166). The shortcoming of those vaccines is the presence of xenogeneic and in reality of ballast antigens that leads to the splitting of immune response between the latter and the antigens determining the specific response against EC.
From another source the vaccine based on allogenic antigens is known, that is a vaccine produced using the cells of other organisms belonging to the same species (e.g. Scappaticci F. A., Nolan G. P., “Induction of anti-tumor immunity in mice using a syngeneic endothelial cell vaccine”, Anticancer Res., 2003, v. 23, 1165-1672, authors of this publication compare different variants of EC vaccines). The presence of allogenic antigens in vaccines also results in the decrease of the strength and of the specificity of immune response to the EC-specific antigens.
The closest analogue is described in the paper of Okaji Y. et al. (“Vaccination with autologous endothelium inhibits angiogenesis and metastasis of colon cancer through autoimmunity”, Cancer Sci., 2004, v. 95, 1, 85-90). The latter method includes the use of endothelial cells. In the above mentioned method autological EC are used i.e. the cells isolated from the organism vaccinated or cells from the genetically identical organisms (e.g. cells from the same line of mice). Such vaccines give a most strong and specific immune response determining the cure effect. But all of vaccines obtained from the whole cells contain a large quantity of ballast material i.e. of cytosol proteins, carbohydrates and lipids. Ballast substances strongly reduce the part of antigens in the vaccine, these antigens being the potential aim for the action of the immune system (intracellular antigens are not available to the effect of the immune system). One should note that an already known method of the preparing of the vaccine does not induce the specific immune response to the EC of tumor vessels namely.
The aim of this invention is the development of the method of preparing EC antigens-based tumor vaccine intended for the overcoming of the immune tolerance of organism to the EC of the tumor vessels. The ground for this invention is a well known difference between the EC of normal tissue vessels, which are in a state of rest under physiological conditions, and the EC of tumors which are activated i.e. are actively proliferating and migrating. It is known that activated EC in comparison with the EC of normal tissue vessels have a higher expression of many specific proteins such as αvβ3 (Gladson C. L. et al., Am. J. Pathol., 1996, v. 148, 1423-1434), E-selectin (Volm M. et al., Clin. Cancer Res., 2000, v. 6, 3236-3240), endoglin (Burrows F. et al., Clin. Cancer Res., 1995, v. 1, 1623-1634), endosyalin (Takahashi K. et al., J. Clin. Invest., 1994, v. 93, 2357-64) and VEGF-receptors (Boocock C. et al., J. Natl. Cancer Inst., 1995, v. 87, 506-516). The difference of expression profiles of some proteins is known from the patents US2006210975, US2005142138, US2006127902 and international application WO 2004091383. As to what concerns this invention most important are the differentiae of the EC surface, particularly of the neutrophillins, integrins, receptors etc which allows to obtain antigens specific for the EC of tumor vessels (see international application WO 2004001004).